This proposal requests funding to permit attendance and active participation of young scientists, predominantly from developing countries, at the Fourth International Workshop on the Oral Manifestations of HIV Infection to be held in South Africa July 4-July 7, 2000. Due to the extreme limitation of funds for young scientists from developing countries to attend meetings of this caliber, the request emphasizes support for foreign participants. Approximately 210 scientists are expected to attend the Workshop. Of these, about half will be from outside the U.S.A., notably from Africa, Asia, Europe, Canada, and Central/South America. All aspects of HIV research as it relates to the mouth will be covered, ranging from basic molecular virology and mycology, through clinical and epidemiological research to psycho-social, behavioral and legal issues. The program emphasizes active involvement on the part of all participants, notably during the topic-specific workshop sessions. Lesions in the mouth were among the first documented features of AIDS. Their varied nature and common occurrence is reflected in an extensive and growing literature. Oral candidiasis in non- AIDS patients who were in high-risk categories was shown early in the epidemic to be predictive of AIDS. With the discovery of hairy leukoplakia, it soon became clear that this was also an indicator of HIV infection and the subsequent development of AIDS. In addition to their role in the diagnosis of HIV infection and as indicators of the progression of HIV disease, oral lesions are used as clinical correlates of CD4 counts, as criteria for entry into clinical trials and as readily studied and accessible models for mucosal immune abnormalities in HIV infection. Their presence relates in important ways to the efficacy and failure of current anti-HIV therapies. Oropharyngeal lesions cause significant morbidity, yet many can be treated using fairly simple therapeutic approaches. Research on this group of lesion ranges from epidemiology and natural history studies, through basic molecular virology, mycology, and mucosal immunology, to social and behavioral studies. At the First International Workshop, held in San Diego in 1988, a handful of pioneers in this new field shared their work with approximately 150 people. Over 300 scientists attended the Second Workshop in San Francisco in 1993, while approximately 350 participated in the Third Workshop in London, UK in 1996. The proceedings of each of the previous Workshops were published and are standard reference sources in the field. The time is now ripe for a Fourth Workshop, during which new discoveries can be integrated and shared with a further group of new investigators in the field, particularly those from parts of the world where HIV/AIDS epidemic is growing most dramatically, notably Southern Africa, the venue for both this meeting and to 2000 International AIDS Conference. It is anticipated that recipients of support from the proposed R13 conference grant will take back to their own programs the knowledge acquired at the Workshop where they will apply it, thus contributing to HIV/AIDS research, care and education in those countries where such improvements are most sorely needed, as well as in North America.